A number of researches are being conducted to provide various types of multimedia services, for example, voice services, and to support high quality and high speed of data transmission in a wireless communication environment. Technologies associated with a multiple-input multiple-output (MIMO) communication system using multiple channels, are also in rapid development to provide various types of multimedia services and to support high quality and high speed of data transmission.
In a MIMO communication system, a base station may support a plurality of users, that is, terminals, using a spatial division multiplexing access (SDMA) scheme. The SDMA scheme may transmit at least one data stream to multiple users via a plurality of antennas. The SDMA scheme may utilize wireless resources more effectively, thereby increasing a data rate of the MIMO communication system. The MIMO communication system supporting the plurality of users may adopt a single beam to support a single user. Accordingly, where the base station includes M transmit antennas, the base station may simultaneously support a maximum of M number of users.
Increasingly, users desire to receive various types of services, and services with various characteristics may be provided. For example, a user 1 may desire a service supporting a large data size with a non-strict delay tolerance. Conversely, a user 2 may desire a service supporting a small data size but with a strict delay tolerance. Here, the strict delay tolerance may indicate that the delay should be short.
Generally, a conventional MIMO communication system does not take into consideration the characteristics of services when scheduling users. Accordingly, in the conventional MIMO communication system, it may allocate a single beam to only one user, requiring a service with small data size, for more than a required period of time. Consequently, wireless resources may not be utilized effectively. Accordingly, there is a need for a method of scheduling users based on characteristics of services desired by the users.